1. Field of the Invention
Embodiments of the present invention generally relate to an organic light emitting diode (OLED) structure and a method for its manufacture.
2. Description of the Related Art
OLED displays have gained significant interest recently in display applications in view of their faster response times, larger viewing angles, higher contrast, lighter weight, lower power, and amenability to flexible substrates, as compared to liquid crystal displays (LCD). In addition to organic materials used in OLEDs, many polymer materials are also developed for small molecule, flexible organic light emitting diode (FOLED) and polymer light emitting diode (PLED) displays. Many of these organic and polymer materials are flexible for the fabrication of complex, multi-layer devices on a range of substrates, making them ideal for various transparent multi-color display applications, such as thin flat panel display (FPD), electrically pumped organic laser, and organic optical amplifier.
The lifetime of display devices can be limited, characterized by a decrease in electroluminescence efficiency and an increase in drive voltage. The limited lifetime may be due to the degradation of organic or polymer materials and the formation of non-emissive dark spots. Material degradation and dark spot problems may be caused by moisture and oxygen ingress. For example, exposure to humid atmospheres is found to induce the formation of crystalline structures of 8-hydroxyquinoline aluminum (Alq3), which is often used as the emissive layer, resulting in cathode delamination, and hence, creating non-emissive dark spots growing larger in time. In addition, exposure to air or oxygen may cause cathode oxidation. Once organic material reacts with water or oxygen, the organic material is dead.
Therefore, there is a need in the art for an OLED structure that does not degrade or form non-emissive dark spots. There is also a need for a method to produce such a structure.